A hearts and arrows pattern is successfully generated by a round cut diamond when exposed to light, provided the round diamond is cut into a nearly perfect round shape possessing equal and symmetrically cut facets with its angular proportions polished within relatively narrow ranges. Unlike the round shaped diamond an oval shaped diamond, by definition, has a non-symmetrical geometry with two long sides and two short sides. Applicant has nevertheless been able to polish an oval shaped diamond to generate a hearts and arrows pattern when subjected to light as shown and taught in U.S. Pat. No. 7,878,025 the disclosure of which is incorporated herein by reference. The hearts and arrows pattern generated in the oval shaped diamond taught in U.S. Pat. No. 7,878,025 simulates the hearts and arrows pattern generated in a symmetrical round shaped diamond.
It has been discovered, in accordance with the present invention, that the shape of the hearts generated in the hearts and arrows pattern can be substantially enhanced both in symmetry and beauty in comparison to the shape of the hearts generated in U.S. Pat. No. 7,878,025 when the oval shape diamond is polished to include a unique crown star faceting arrangement having a crown star facet containing two facet sections of equal size and geometry in each of the two long and two short sides of the oval shaped diamond and having a crown star facet containing two facet sections of non-equal size and geometry in each of the four diagonal or shoulder sides of the oval shaped diamond. In the preferred embodiment the non-equal parts in each crown star facet on the diagonal sides of the oval shaped diamond are essentially equal to one another in both size and shape respectively.
The improved oval shaped diamond of the subject invention preferably comprises eight main crown facets and eight main pavilion facets with each of the eight main crown facets having a perfectly parallel opposite main crown facet and with each of the eight main crown facets being perfectly aligned with a main pavilion facet positioned on to it. None of the eight main crown facets or eight main pavilion facets should be aligned on the short or long sides of the diamond.
It is also preferred to polish the oval shaped diamond of the subject invention such that none of the eight main crown facets are in alignment with the shape of the oval and, in fact, the diamond should be polished such that four of the eight main crown facets, which lie at least partly on the short side of the diamond, be in substantial misalignment with the shape of the oval and that the other four main crown facets, which lie at least partly on the long side of the diamond, be only slightly misaligned with the shape of the oval. This arrangement results in a highly uneven girdle thickness throughout the diamond, i.e., the girdle thickness varies widely throughout the diamond. However, the degree of variation in the thickness of the girdle is minimized in accordance with the subject invention by further polishing the oval shaped diamond of the subject invention so that it includes a multiple number of subsidiary pavilion facets, preferably twelve in number, with all of the subsidiary pavilion facets located symmetrically on opposite pavilion sides of the diamond extending between its diagonal shoulder sides and with none of the subsidiary pavilion facets lying on either short side of the diamond.
Moreover, the improved oval shaped diamond of the subject invention comprises 16 crown halves (half facets) and that, preferably, sixteen of the crown halves do not meet one other at a point halfway on the main crown facets as is typical in a conventional oval shaped diamond having eight main crown facets and 16 crown halves.